Within the context of a healthy and balanced diet, more related to our sedentary lifestyle, there is a need for food compositions which meet the requirements, on the one hand, for a reduced calorie, fat and sugar content and, on the other hand, for a high dietary fiber content and which promote the development of a beneficial intestinal flora.
These food compositions must, in addition, meet organoleptic qualities (appearance, texture, taste, mouth feel) which cannot be inferior to traditional foods.
Fructans such as inulin can meet these requirements.
Accordingly, the product RAFTILINE.RTM. was developed and marketed by Raffinerie Tirlemontoise. RAFTILINE.RTM. has advantageous nutritional properties which make it possible to satisfy the requirements of a balanced diet as set forth above. Its bifidogenic effect, its behavior as dietary fiber and its very low calorific value (.apprxeq.1 kcal/g) may be mentioned.
From the organoleptic point of view, RAFTILINE.RTM. is characterized by a slightly sweet taste (10% of that of sucrose) without aftertaste and by a neutral odor.
One of the functional properties of RAFTILINE.RTM. which limits its use in the abovementioned food compositions is its solubility.
RAFTILINE.RTM. contains inulin, a substance which can be easily obtained from many widely distributed plants, more specifically in the case of RAFTILINE.RTM., from the chicory Cichorium intybus.
Inulin is a polydispersed composition of saccharides of general formula GFn (G=glucose, F=fructose, n=number of linked fructose units (n.gtoreq.2), the fructose units being linked to each other essentially by .beta.(2.fwdarw.1) bonds.
Being a mixture of molecules of different lengths, the degree of polymerization (DP=n+1) of chicory inulin varies from 2 to more than 60.
The degree of polymerization is an important parameter since it influences the solubility of inulin.
RAFTILINE.RTM. is very sparingly soluble. Dissolution of inulin depends on the desired final concentration and the temperature. Thus, for example, complete dissolution occurs only at temperatures greater than 85.degree. C. At 60.degree. C., an aqueous solution may be obtained containing 25% inulin. However, at room temperature, only about 10% of inulin having a mean DP of about 9 can be dissolved in water.
The accompany FIG. 1 represents the curve of solubility of RAFTILINE.RTM. ST as a function of the temperature.
It is therefore practically impossible to add concentrated inulin solutions to food preparations.
One alternative consists in the incorporation of inulin in powdered form but the disadvantage of this is that the food products obtained often have a sandy texture. Furthermore, it is often very difficult, if not impossible, to add large quantities of inulin powder to food products such that the inulin is evenly dispersed therein. The formation of lumps and the appearance of a deposit is for example observed.
In order to overcome these disadvantages, the Applicant has developed and described in the patent application published under the Ser. No. WO93/06744, compositions having a creamy structure and comprising fructan or a mixture of fructans (e.g. RAFTILINE.RTM.) and a liquid. The fructans are the essential element for the formation of the said creamy structure. The patent application also describes the process for preparing these compositions and their use.
These compositions having a creamy structure are only obtained by subjecting the fructan(s) and the liquid to high shearing forces.
A range of creams can thus be prepared whose inulin concentrations vary from 5 to 85% or more, and preferably from 20 to 50%.
However, in order to provide high shearing forces, these preparation processes require the use of mixers, ultrasound reactors, ball mills, homogenizers, colloid mills and/or high speed shearing appliances such as hydroshear or an Ultra-Turrax.RTM..
Such appliances are often expensive and difficult to use when large volumes of "cream" have to be produced.
Furthermore, during the preparation of the creamy-structured composition, deposits and/or lumps may form inside the composition and/or on the shearing appliances, which disrupts the organoleptic properties of the food products into which the said composition is incorporated and/or makes their preparation difficult.
In the food sector, an agglomerated composition which results from an agglomeration process is generally called a "soluble product" or alternatively a "minute product". The food product which is obtained after a liquid has been added is often called an "instant" product".
Thus, instant food products in liquid form comprising inulin are known.
In the case of "soluble tea" as described in the document EP-524,484, the inulin is used as support material for the flavor components and other extracts of the raw material. In instant tea, the inulin can be solubilized.
FIBRULINE.RTM. Instant is also known (Cosucra, Belgium). It is a powdered inulin composition which has a larger mean grain size than the standard powdered FIBRULINE.RTM. (Cosucra, Belgium) and which is reportedly easier to solubilize.